Georges Sagnac

Georges Sagnac was a French physicist best known for his work in the early 20th century on the nature of light and motion. He conducted the Sagnac experiment in 1913, which demonstrated that light travels at different speeds depending on the direction of motion of the observer. This finding posed challenges to the then-accepted theories of relativity and contributed to the understanding of how light behaves in rotating systems. His work is foundational in modern physics, influencing areas like optics and the development of technologies such as GPS, which relies on precise measurements of time and light.